Theodolite or similar instrument.



No. 848,132. PATENTED MAR. 26, 1907.

G. P. E. SCHNEIDER & E. RIMAILHO. THEODOLITE 0R SIMILAR INSTRUMENT.

APPLIUATION FILED AUG.21, 1906.

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wncv w A c Jay] UNITE STATES PA QFFICE.

CHARLES PROSPER EUGENE SCHNEIDER, OF LE CREUZOT, AND EMILE RIMAILHO, OFNEUILLY-SUR-SEINE, FRANCE.

THEODQLITE OR SIMILAR INSTRUMENT.

Specification of Letters Patent.

Patented March 26, 1907.

Application filed August 21, 1906. Serial No. 331,483.

To and whom it may concern.-

Be it known that we, CHARLES PROSPER EUGENE SoHNEInER and EMILERIMAILHO, residing, respectively, at Le Creuzot, Saone et Loire, France,and at 54 Boulevard Maillot, N euilly-sur-Seine, Seine, France, haveinvented a new and useful Improvement in or Relating to Theodolites orSimilar Instruments, which is fully set forth ing specification.

The present invention has for its object a field-theodolite whichalthough very small in bulk and easily transportable constitutes aninstrument of great precision for the measurement of azimuthal andzenithal and bearing or direction angles relatively to the magneticnorth.

In carrying out reconnaissances, surveying, or like operations inconnection with tracts of country it is necessary for the surveyor orofiicer, for example, to measure azimuthal and zenithal angles, forwhich purpose an mstrument of great precision and capable of beingreadily transported by a horseman is required.

The apparatus hereinafter described is designed with the object offulfilling these conitions, and, further, to permit either of takingbearings with precision on the magnetic north or of measuring distances.

A theodolite constructed. according to this invention is represented indetail in the accompanying drawings, in which Figure 1 is asideelevation. Fig. 2is alongitudinal section on the line A A of Figs. 3 and4. Fig. 3 is a horizontal section on the line B B of Fig. 2. Fig. 4 is aplan view. Figs. 5 and 6 are diagrams illustrating methods of employingthe apparatus.

The apparatus is constituted in principle by a supporting or containingbox a for the sighting and observing parts, the box being adapted forreceiving a rotary movement about a rod 6, which traverses the said box.For this purpose the surface of the said rod 12 is cut in the form of atangent screw-wheel, which is divided into two parts 8 t to enable playof the parts to be taken up, a spring ac serving to insure the alinementof the said parts. Movement of rotation is given to this tangent-wheelby means of a screw 0 on a spindle g, carried by the box a.

If the rod 6 s the supported by an external projection-such as thatindicated at (Z, for exin the followf ample-and if the screw 0 beactuated directly or by means of a handle h, mounted in a part of thebox and carrying the pinion 'i, which meshes with the pinion 0, keyedupon the spindle g, which carries the screw 0, the box a will be causedto rotate about the rod '6 and the amplitude of this movement may bedetermined by means of graduated circles e respectively, carried by therod 6 and the spindle g of the screw 0.

In the constructional form represented the projection d of the rod 1)carries a spherical head, which may be mounted upon a tripod p by theintermediary of a ball-and-socket joint Q, Figs. 5 and 6. h A part ofthe box a forms a sleeve j, parallel with the spindle g, for thereception of a magnetized declinationneedle 76, and it is this sleeve(at the respective extremities of which there are arranged an eyepieceand a lens Z and a ground glass m, provided with a guide-mark) whichserves as the axis of rotation for a powerful prismatic telescope a(magnifying largely) and of small length, provided internally with amicrometer. It follows from this construction that the tele scope itparticipates in the movements of rotation of the box a around the rod 1)ts and that it is also able to turn in a plane parallel with the axis ofrotation of the said box, moving in front of a graduated scale y,carried by the box a, which permits of readin the value of itsinclination to the horizon.

The apparatus is completed by two levels n and 2' and a compass 1,arranged in a recess o of the box a and covered with ahinged lid w.

The theodolite described may be employed in the following connections:(a) as a means of measuring the horizontal angle comprised between theplanes of direction of two objects situated at different heights (b) asa means of measuring the horizontal angle comprised between the plane ofdirection of an object and the vertical plane passing through thetheodolite and the magnetic north,- (0) as a means of measuring theangle above or below the horizon made by a line proceeding from thetheodolite and terminating at any desired point; (01) as a means ofmeasuring the dlstance of a distant point by the employment of twotheodolites and of an ap ropriate calculation-circle. The theodolitebeing placed upon its support, Fig. 5, the axis of the rod 7) is atfirst rendered vertical by the rotation of the ball-and-socket joint bybringing the bubble of the spherical level n to the center of thislevel. If the operatinghandle it be rotated, the telescope a will retatewith the box at around this vertical axis. It is directed toward a firstobject, and the telescope is inclined around its axis of rotation inorder to direct it onto the object situated either above or below thehorizon. The angle made by the axis of the telescope with the horizontalis then read on a graduated scale y. The telescope being directed ontoan object, the graduations of the upper disk 6 and of the lateral disk fdefine this direction, starting from the zero of the graduations, by acertain number. For example, the upper disk is divided into sixty parts,each equivalent to one hundred units and numbered 0, 100, 200, 5900. Thelateral disk is divided into one hundred parts, numbered 0, 1, 2, 99.The index 1 of the upper disk being brought to rest be tween 4200 and4300, the index 2 of the lateral disk being brought to rest at 7 5, thedirection of the telescope will be defined by the figure 4275. As soonas the lateral disk f is caused to rotate through a division thetelescope u rotates around the rod 1), and the fresh direction isdefined by the figure 4276 or 4274, according to the amount or directionof rotation. Further, the unit of measurement being one six-thousandthof the circumference, the arc described by a point of the axis of thetelescope u in order to pass from the origin of the directions to thedivision 4275 has for its value four thousand two hundred andseventy-five six-thousandths of the circumference. The angle of rotationof the telescope has thus been measured. This operation may be repeatedin succession for all the points situated around the vertical axis ofthe theodolite and define the direction of each of them and measure theangles comprised between these directions. Among these points it may bedesirable to define that which is in the direction of the magneticnorth. In this case the theodolite should be rotated until themagnetized needle in is in equilibrium in front of a guide-mark carriedby the ground glass m. It is directed to the north, and the telescope a,which is fixed at ninety degrees to the right of the axis of the needle,is directed to the east. As, further, the graduated disks 6 f aremovable with slight friction on the rods 6 and g, respecl l l l i l i ltively, the instrument may at this moment be caused to mark zero, andall the subse quent displacements of the telescope will be measured froma fixed origin obtained by directing the instrument to the magneticnorth.

If the theodolite is arranged as indicated in Fig. 6, its axis ofrotation 1) having become horizontal the box a moves in a verticalplane, and its rotation and that ol the telescope are always recorded bythe graduated disks cf. As the lateral face, which is now above, carriesa level 2, fixed parallel with the axis of the telescope, means 'eavailable for rendering the axis of the telescope horizontal. Theindexes l. and 2 are then caused to mark zero. Ii the telescope 'lt isthen inclined upward or downward, the angle through which it has turnedlrom the horizontal is registered by the graduations ol 1 What I claim,and desire to secure by Letters Patent oi the United States, is

1.. In a theodolite or similar instrument, the combination of asupporting-box provided with sighting and directing parts, a rodprovided with a two-part tangent screwwheel, an operating-screw engagingsaid wheel for rotating said box, said rod and opcrating-screw carryinggraduated sales to serve for indicating the amplitude ol' the movementol rotation.

2. In a theodolite or similar apparatus the combination of a telescope,a supporting-box and a sleeve formed therewith and adapted forcontaining a magnetized declination-needie, the said sleeve serving asthe axis ol' rotation for the sightingtelescope, substantiall ashereinbefore described for the purposes specified.

3. In combination, a spring-pressed twopart shaft having a two-parttangent screwthread, a box or casing revolubly mounted on said shaft andprovided with a telescope, and a drive-shatt having a worm-gear engagingsaid first shalt for rotating said casing.

In testimony whereol we have signed this specification in the presenceof two subscribing witnesses.

CHARLES lliOSllill- EUGENE SCllNlllllllll. llilllhil lllllAlhllO.

Witnesses:

EUGENE Enassnn, PIERRE GABON.

